A Range Extension Method for Laser Tracker to Reduce Abbe Error.

This paper presents a systematic optical range extension method for laser tracker calibration in a limited indoor space. The method is based on optical path folding using pyramid prisms and is designed to quantitatively reduce Abbe error. Both approaches realize dual-range measurement of laser trackers within confined indoor baseline space. Experimental results reveal that calibration tests carried out over an 80 m distance with dual pyramid prisms yield a maximum indicated error of -36.0 µm for the laser tracker, whereas the configuration adopting a single pyramid prism delivers a maximum indicated error of merely -2.7 µm. When the two measurement systems share a pyramid prism, the shortened Abbe arm effectively diminishes Abbe error. Additionally, the optical symmetry between the incident and emergent light beams further suppresses such error, leading to a lower indicated measurement error. Relevant experimental data confirm that the optical path layout using a single pyramid prism offers superior measurement precision. The experimental data show that the optical path experiment using a single pyramid prism has higher measurement accuracy. We hope the related results could serve as a reference for multiple range-extension measurements with the laser tracker.